This invention relates to a pull-in device for imparting a vertical reciprocation through a string to a rear shelf disposed on a rear receiving compartment side as interlocked with a make-and-break action of a tailgate of a hatchback car, for example.
The invention disclosed in JP-A-SHO 57-194165 concerns one of the conventional pull-in devices of this class.
This conventional pull-in device, as illustrated in FIG. 2 through FIG. 4 of this disclosure, is constructed by providing opposite sides on a rear face of a rear shelf with a pair of cover members. Inside each of the cover members is disposed an elastic member having one terminal part thereof fixed on the cover member side. One terminal part of a flexible member is connected to the other terminal part of the elastic member, and the other terminal part of the flexible member is fitted on the tailgate side of a hatchback car.
In the conventional pull-in device, when the tailgate of the hatchback car is opened, the rear terminal part side of the rear shelf disposed in the rear receiving compartment is moved upward by the tensile force of the flexible member to permit the baggage to be moved in or out of the rear receiving compartment. Conversely, when the tailgate is closed, the rear shelf moves downward under its own weight and resumes the original horizontal state. At this time, the presence of the flexible member causes no obstruction because the flexible member is pulled into the interior of the cover member by the elastic force of the elastic member.
The conventional pull-in device, therefore, provides an advantage in enabling the rear shelf to be automatically reciprocated vertically as interlocked with the closing and opening motion of the tailgate. On the other hand, it provides a disadvantage in requiring the cover member to be unduly elongated for the purpose of imparting an ample length to the flexible member and causing it to be automatically enlarged in the direction of the length thereof.
This invention has been developed with a view to effectively solve the problem entailed by the conventional pull-in device as described above.
This invention relates to a pull-in device for a string, which comprises a tubular cylinder, a piston adapted to move inside the cylinder, an urging spring for elastically urging the piston inside the cylinder in the direction of one terminal part thereof, and a string to be pulled in or pulled out in consequence of the movement of the piston. In this pull-in device, a plurality of hooking parts, each capable of slidably hooking the string, are formed on the piston mutually opposed across the center of the piston, and a hooking part capable of slidably hooking the string is formed on a cap adapted to close the other terminal opening part of the cylinder. One terminal part of the string can be pulled out of the cylinder and meanwhile, the intervening points of the whole length of the string can be hooked serially on the hooking parts as folded back, and the other terminal part of the string can be fixed on the cylinder or piston. As a consequence of this procedure, the string can be given a far greater length than the length of the cylinder and the pull-in device itself can be miniaturized to a great extent. Since the hooking parts on the piston side are formed mutually opposed across the center of the piston, the piston can be smoothly moved inside the cylinder without producing any rattling motion.
The pull-in device of this invention is provided between the cylinder and the piston with a rotation-preventing means capable of preventing the piston from being rotated inside the cylinder. As a result, the string hooked on the piston side inside the cylinder can be prevented from entangling.
This invention contemplates allowing the piston to deform elastically and go through the inside of the urging spring and force its way under the spring seat of the urging spring disposed on one terminal part side of the cylinder. During the assembly of the device, by enabling the piston to go through the whole route thereof after the urging spring has been inserted into the cylinder, it is made possible to advance the piston to below the spring seat of the urging spring disposed on one terminal part side of the cylinder. As a result, it is possible to enhance the overall ease of the assembly of the device.
This invention contemplates defining a sealed chamber between one terminal part of the cylinder and the piston and providing the sealed chamber with a valve having a directional property such that the valve permits air to flow in when the piston has moved in the direction of the other terminal opening part of the cylinder and restricts the inflow of the air when the piston has moved in the direction of one terminal part of the cylinder. As a consequence of this contrivance, the string, when pulled in freely, is prevented from rattling vigorously around.
This invention contemplates providing the piston with an orifice such that when one terminal part of the string is to be pulled in freely, the greatest speed of the movement of the string is kept from exceeding 1.6 m/sec. The string cannot be pulled in at an unduly high speed because a braking force is exerted on the speed of movement of the string as a consequence of the contrivance.
This invention contemplates providing one terminal part of the urging spring with a means for preventing the piston from being rotated and the other terminal part thereof with a means for preventing the cylinder from being rotated. In consequence of this contrivance, the string hooked on the piston is prevented from entangling.